Electrically-actuated signaling device



July 13, 1954 G. R. FISH ELECTRICALLY-ACTUATED SIGNALING DEVICE 4Sheets-Sheet 1 Filed March 20. 1951 July 13, 1954 G. R. FISHELECTRICALLY-ACTUATED SIGNALING DEVICE 4 Sheets-Sheet 2 Filed March 20,1951 //V VE'N 70/? GEORGE A. F/6/-/ Patented July 13, 1954ELECTRICALLY-ACTUATED SIGNALING DEVICE George R. Fish, Norwalk, Conn.,assignor to Edwards Company, Inc., N orwalk, Conn., a corporation of NewYork Application March 20, 1951, Serial No. 216,561

40 Claims.

This invention relates to electrically actuated mechanisms, particularlyelectric signalling devices such as an electric bell.

One of the objects of this invention is to provide a practical andefiicient electric signalling device which is constructed to providedependable safeguards against foreign matter, such as water, moisture,dust, and the like, or against the hazards of explosive atmospheres, andthereby achieve reliable maintenance and safety of operation of thedevice. Another object is to provide a device of the above-mentionedcharacter which is simple and practical in construction and assembly,may be installed with facility, and well adapted for long continued useor operation under adverse conditions such as those just mentionedabove. Another object is to provide a signalling device that is welladapted to withstand the varying conditions of use and operation onshipboard, such as humidity, water, including submersion, and widechanges in temperature, including freezing temperatures, and the like.

Another object is to provide an electric gong signalling device in whichthe electric actuating parts are dependably protected and sealed, forexample, against the elements of weather or the like, and yet the gongstriker maintained unimpaired in achieving the desired audiblesignalling. Another object is to provide a gong and striker mechanismthat is capable of dependable operation under conditions of moisture,wetness, rain, and even freezing; another object is to carry out thislast-mentioned object by a construotion that is well adapted forfabrication, assembly, and installation. Another object is to provide anelectric bell or like signalling device that can be safely operatedthroughout a wide range of varying conditions of practical use andmaintain reliability or dependability of actuation.

Another object is, in general, to provide an improved device of theabove-mentioned character. Other objects will be in part obvious or inpart pointed out hereinafter.

The invention accordingly consists in the features of construction,combinations of elements, and arrangements of parts as will beexemplified in the structure to be hereinafter described and the scopeof the application of which will be indicated in the following claims.

In the accompanying drawings, in which similar characters refer tosimilar parts throughout the several views,

Figure 1 is a front elevation of the signalling device as installed inuse;

Figure 2 is a side elevation as seen from the right in Figure 1, certainparts being broken away to show certain other parts more clearly;

Figure 3 is an exploded view as seen from the right in Figure 1 or fromthe front in Figure 2, showing also the internal striker actuatingmechanism in one form or embodiment thereof;

Figure 4 is an elevation as seen along the line 4-4 of Figure 3;

Figure 5 is a vertical sectional view as seen along the line 55 ofFigure 3;

Figure 6 is a fragmentary sectional view as seen along the line AA ofFigure 1, showing the relationship between gong, striker, and one formof striker actuating mechanism;

Figure '7 is a detached elevation of a sub-aw sembly as seen along theline 'l-'l of Figure 6;

Figure 8 is a detached elevation of a modification of the sub-assemblyof Figure '7, as see along the line '!1 of Figure 6;

Figure 9 is an electrical diagram showing the connections in theembodiment of Figure 8;

Figure 10 is a fragmentary sectional View like that of Figure 6 showingthe striker actuating mechanism arranged for ice-breaking and therelationship therebetween and the gong and striker;

Figure 11 is a fragmentary sectional view as seen along the line A-A ofFigure 1, showing another form of construction for achieving certainother advantages and constructed for optional employment of the featureof ice-breakmg;

Figure 11 is a detached fragmentary portion of the view of Figure 11, onan enlarged scale, to show certain features more clearly;

Figure 12 is a detached elevation of the subassembly employed in Figure11, being a fragmentary elevation as seen along the line l2-i2 of Figure11;

Figure 13 is an electrical diagram showing a possible form of circuitconnections in the form of Figures 11 and 12;

Figure 14 is a detached elevation of a modified form of sub-assembly asseen along the line EL -I2 of Figure 11;

Figure 15 is a fragmentary sectional view as seen along the line A-A ofFigure 1, showing a modified form of construction adapted to achieveother advantages;

Figure 16 is a detached elevation of the subassembly employed in theform of Figure 15 and illustratively embodying an interrupter;

Figure 17 is a view like that of Figure 15 show- 3 ing the mechanismarranged for ice-breaking; and

Figure 18 is a diagram of the circuit connections employed where thedevice of Figures -17 employs an interrupter.

Referring to Figures 1, 2, and 3, I provide a casing which preferablycomprises two separable parts which, when assembled, form a sealed orairtight enclosure; in the preferred form illustrated, this casingcomprises companion parts 28 and 2|, of which the part 29 may beconstructed in the form of a box and the part 2| in the form of aclosure or cover plate therefor. The part 28 may have a bottom wall 22and side walls 23 and they are provided with a suitable knock-out, oneof which is shown in Figure 2 at 24, whereby to provide a hole oropening through which a conductor-carrying conduit (not shown) may bemechanically secured and placed in sealed connection therewith in anysuitable or known manner,

thus to extend the electric circuit to the interior of the casing. Thelatter may be mounted in desired position in any suitable manner and,for example, if it is to be surface-mounted, the boxlike casing part maybe provided with apertured ears or lugs 25 by which they may be boltedor otherwise secured to a wall or other support.

The conductors (not shown), usually two in number, thus brought into thecasing are connected to binding screws 26 (Figures 5 and 3) of thesocket part 2? of a separable two-conductor plug and socket connectingdevice, the plug part 28 (Figures 4 and 3) of which is carried by thecompanion casing part 2| in a manner later described. These separableconnector parts be or" any suitable construction. The socket connectorpart 2?, comprising a suitable body of insulating material, is secured,as by screws (not shown), to a bracket plate 3|) stepped, as shown inFigures 2 and 3, to have a portion overlying a heavy boss 34 castintegrally with the casing wall 22 to provide good support for screws 32by which the bracket 38 is secured to the boss 3 I The boss 3i makes itunnecessary to drill the screw holes through the back wall 22.

As shown in Figure 5, the socket-connected part 2'! has two spacedrectangular sockets or recesses 27 into which the two contact prongs 28of the plug part 28 enter for making internal connection with thecircuit of the conductors connected to the binding screws 26. The plugconnector part 23 is rigidly mounted on the inside face of the coverplate 2| by means of a U-shaped bracket $3 to the cross-part of whichthe insulating body of the plug part 28 is secured, as by screws (Figure4), the two arms of which U-shaped bracket being secured to the coverplate 2| in any suitable manner, as by stepping them (see Figure 3) attheir free ends for reception in suitable spaced holes 3Q (see Figures 1and 3), whereupon the reduced ends are peened or headed over. Theresultant cold-flow of metal not only securely anchors each bracket armto the front plate 2 l, but also expands the metal into the respectiveplate holes and achieves a good sealed joint, particularly where themetal of the parts is the same and of a composition like brass. The plugpart 28 is provided with suitable means, such as conductive tabs or ears28 (Figures 3 and 4), for securing the ends of conductors of theelectric actuating mechanism, the connectors 28 being internally inconnection with the respective prong parts 28*.

The separable plug and socket connector thus coacts to insure that thecompanion casing part must always be assembled to the mounted or securedcasing part in the same way, and thus they coact to orient the companioncasing parts upon assembly thereof. The companion casing part 20comprises also a re-entrant casing part in the form of a metal tube 36,of brass, for example, that is closed or sealed 01f at its inner end, asat 36 (see also Figure 6), and it is integrally secured to the frontplate 2| so that it extends upwardly and inwardly into the box-likecasing part 20 at an inclination to the front plate 2| such that itmakes an angle to the plane of the plate 2| substantially as shown inFigure 3 and makes an angle to the vertical axis XX as seen in Figures 1and 4, substantially as is better shown in Figure 4, intersecting theplate 2|, preferably at a point laterally displaced from the axis XX (tothe right in Figure 4 and to the left in Figure 1). As is better shownin Figure 3, the reentrant casing part or tube 36 projects somewhatthrough and beyond the external face of the plate 2|, the latter beingprovided with a suitable elliptical or oval hole (Figure 6) into whichthe metal tube 36 fits and to the walls of which it is secured,

' as by brazing, as indicated at 31 in Figure 6. The

part 36 is thus securely held at the above-described angularities to theaxis XX, the angles being substantially on the order of magnitude asindicated in the drawings, and the brazed or soldered junction 31 makesa sealed joint.

The casing part 29 (Figures 1 and 3) may be provided with a peripheralflange 38 which underlies the marginal portions of the front plate 2|;in this marginal portion of plate 2| and in the casing flange 38 areprovided suitable means that can coact with the plug and socketconnector 21-28 to prevent assembly of the companion casing part 2|-36to the casing part 28' excepting with the axis XX always vertical andwith the re-entrant casing part 38 therefor always projecting upwardlyand inwardly into the box-like casing part 20 and thereby also maintainthe angularity shown in Figure 4; this means may comprise holes 38 and38 conveniently on a diameter, in the flange 38 and studs 4-0 in themaginal portion of the front plate 2| for entry into the holes 38 and 38The socket connector part 27 (Figure 5) is positioned transversely ofand near the lower end of this vertical axis, and so is the plugconnector part 28, the contact prongs of the latter entering the socketcontacts of the former as the studs 4% enter the holes 38 and 38 The twocasing parts are preferably detachably secured together and theirjunction sealed, as by screws 4| that pass through suitable holes in themarginal part of the closure plate 2|, being threaded into suitablebosses 38 formed in the casing flange 38. Projecting forwardly from theflange 38 is a circular gasket-locating flange 42 (Figures 1 and 3)which may be of the same diameter as that of the wall 23 of easing part20 and of which it forms a part where, as is preferred, the flange 38 isseparately constructed as a ring or collar and secured to the casingwall 23, as by brazing or the like, indicated at 43 in Figme 3; a rubberring gasket .44 is seated in the external angle between the flanges 12and 38, and when the screws 4| are tightened up, the gasket iscompressed and forms a continuous seal between the plate 21 and thecasing wall 23 (Figure 2), portions of the bosses 28 limiting the extentto which the screws M can draw the parts 2| and 20 together and actingto maintain them parallel. p

assuring uniform compression of the gasket 4 throughout.

Externally of the resultant sealed enclosure and in appropriate relationto the open end 36* of the re-entrant casing part 36, I mount asignailing means that is to be actuated by the electro-responsive means(later described) that is housed within the enclosure; in theillustrative embodiment, this signalling means comprises a gong 4-5positioned to overlie the projecting part of the part 36 (Figures 1, 2,and 6) being securely fastened to a large stud or post 46 secured to theplate 2| and positioned on the axis XX (Figure l) Post 35, preferablycircular, is provided with an end face 56 which is conformed as nearlyas possible to the inside face of the central portion of the gong 55 toprovide a substantial supporting area therefor; a screw 4?, providedwith a lock washer, passes through a central hole E5 in the gong and isthreaded into a threaded hole in the post 26 to clamp the gong 45 inposition, and preferably there is interposed between these two parts adisc-like washer of a relatively hard but somewhat yieldable material,preferably nonmetallic, such as hard fiber or hard rubber, and i capableof yielding somewhat under the clamping pressure to conform itself toslight irregularities in the adjacent gong and post surfaces and therebyinsure substantially uniform clamping pressure throughout.

Before assembling the gong to the post 46, there is inserted into there-entrant casing part a gong striker in the form of a rod 59 and anactuator therefor in the form of a paramagnetic plunger 5 i, preferablywith a spring 52 interposed between the sealed end 35 and the inner endof the plunger 5|, as is indicated in Figure 6. The spring is preferablymade of a material like Phosphor bronze. The plunger 5| and the striker5t! are made corrosion-resistant in any suitable way; for example, theplunger 5| may be or" soft iron, chrome-plated, and the striker rod 555may be of stainless steel. The spring 52 is well protected, beingcompletely enclosed between the inner end of plunger 5| and the sealedend of the tubular casing part 36 whose interior surface serves as aguidway for reciprocating movement of the plunger 5|, the relativediameters providing ample clearance, on the order of several thousandthsof an inch, for adequate freedom of reciprocating movement throughoutthe conditions of practical use. Some compression or expansion of airbetween the inner end of plunger 5| and the sealed tube end 36 may takeplace during the strokes of reciprocation of the plunger, the air inthat inner end space functioning somewhat like a spring, being desirablyrelieved to the desired extent by leakage in the clearance between theplunger and its guiding tube wall. Where, as is preferred, spring 52 isemployed, the just-described action can serve to supplement the actionof the spring itself.

In normal or at-rest position, the parts 55 and 5!, tending by theirweight to slide downwardly (Figure 6), are preferably given a positionwherein the striker 5G is out of contact with the gong is; this is ofadvantage in that water, as from condensation or rain or the like, thatmight run down along the inside surfaces of the gong 45, as viewed inFigures 1 and 2, is prevented from accumulating as it would at the pointor area of engagement between the striker and the gong surfaces; suchwater runs to and tends to accumulate as it spills off on the insideface of the peripheral or skirt portion 45* (Figure 6) at the six oclockposition as seen in Figures 1 and 2, where in sufiiciently lowtemperatures it might freeze and build up as it freezes. But the loweropen end of the tubular casing part 36, while terminating close to theinside surface of the skirt-like gong portion is juxtaposed to thatportion of the gong at a point angularly displaced from this six oclockposition, illustratively at about the '7 oclock position as shown inFigure 1, so that the striker 5|] can impact against the gong 45 in aregion free from accumulated water or ice, the withdrawn at-restposition of striker ts coacting toward achieving these advantages.Moreover, under such illustrative adverse weather conditions, theplunger and striker remain well protected as no water or the like canenter and remain in the tubular casing part 36, the externallyprojecting portion of the latter giving good protection, particularlyagainst water running down the outside face of the cover plate 2|. Evenif the structure as viewed in Figures 1, 2, and 6 were to be submergedor a water level rise above the lower end of re-entrant casing part theplunger 5| and the surfaces of part 35 along which it reciprocates, aswell as the spring 52, remain dependably protected because the trappedair in the re-entrant casing part 35 prevents rise of water into thepart 36; not only is dependable reciprocating action of the plunger 5!maintained under such conditions, but when those conditions are removed,the actuating parts remain unimpaired. The part 35 is also preferablycorrosion-resistant, and while for some purposes it may be made of brassor the like, it is preferably chrome-plated or it may be made ofstainless steel.

Within the sealed casing 2B2|-36 and assembled to the inwardlyprojecting portion of the tubular casing part 36 is a winding (Figures3, 4, and 6) for producing a magnetic field and to coact in theactuation of the external paramagnetic plunger 5|, receiving its energyby suitable conductors connected to the connector tabs 28 of the plugconnector 28 (Figure 4). Wind ing 55 is preferably wound in the form ofa solenoid winding, for which the plunger 5| is the movable core, andpreferably it is constructed as part of a sub-assembly unit. The winding55 is wound upon a form or spool which may comprise a sleeve 55 and endplates 51 and 58 of suitable insulating material, such as hard fiber,having an internal diameter so that it may be easily slid onto thetubular casing part 36. It is preferably secured to a flat supportingplate 60 (Figures 3, 4, 6, and 7), shaped substantially as shown inelevation in Figure '7, having a relatively large cut-out or openinginto which a portion of the winding unit projects; one of the insulatingend plates 53 is extended, as at 58 (Figures 3 and 6) to projectmaterially to the other side of the supporting plate Bil, and in theextension 58 are secured, as by eyelets, connector tabs El and 52 towhich the ends of the winding 55 are permanently connected and to whichthe conductors that lead to the connector plug 26 may be connected, asby soldering, as indicated in Figure 3.

On the inside face of cover plate 2| are secured two spaced brackets 63and 64; these may be of heavy brass sheet material, and each issubstantially a right-angled triangle in shape with the hypotenuseresting against the cover plate 2| (Figure 3). These brackets aresecured to the plate 2| in any suitable manner, as by integral ears orlugs formed thereon and that extend into suitable spaced holes in theplate 2| where they are peened or riveted over, as at 63 and 64 (Figurel), to form sealed joints. Brackets 53 and 64 are proportioned so thatthe flanges 63 and M thereof fall in a plane that is parallel to theaxis of the tubular casing part 36. It is onto these parallel flanges63* and 64 that the plate support 50 (Figure 7) slides as thesub-assembly of winding and plate support is assembled to the tubularcasing part 36 by entering the inner end of the latter into thecylindrical bore of the winding sub-unit or spool. The plate support 65is provided with slots 65, 66 (Figures 4 and 7) which are parallel toeach other and parallel to the axis of the bore of the solenoid winding,and through the slots extend screws 61 and 68 (Figure 4) whereby thesub-unit may be adjusted lengthwise of the tubular part 36 and set andsecured in a position to achieve the best coaction with the plunger thisadjustment and setting is done empirically during assembly and testing.

Since gongs like the gong 45 are usually shaped out of suitably heavysheet metal, there might be non-uniformity in thickness or the hole 55(Figure 3) might be a bit off center. Such factors as these might upsetthe efiect of the abovedescribed internal setting of the winding andrelated parts were the gong to partake of rotary displacement or were itto be removed and then put back in some other rotary position.Accordingly, at a suitable point offset from the center, I provide inthe gong supporting post 516 a pin 19 (Figures 1 and 3) that projectsbeyond the end of the post, and in the gong 45 I provide a hole H intowhich the pin is received and fits upon securing the gong to the post.The pin thus coacts to prevent rotary displacement of the gong and also,where one is employed, of the semihard interposed pressure distributingmember 48 (Figure 3).

The winding 55, in so far as certain features of my invention areconcerned, may be energized in any suitable manner to achieve thedesired actuation of the plunger 5| and striker 50 for either single orrepeated striking of the gong 45. If a circuit interrupter is employed,as is usually the case for direct current operation, the interrupter isalso contained within the sealed housing and any sparking is renderedharmless, permitting the structure to be used with safety in explosiveatmospheres. Sometimes, for alternating current operation, a rectifieris employed to utilize the pulses of half-waves, and in such case therectifier is also housed in the sealed casing and similar safety ofoperation achieved. Such additional devices I preferably assemble toform part of the sub-unit that comprises the Winding 55 and platesupport 66, connecting the devices in circuit with the winding on thesub-unit and leaving the terminal connector conductors, leading from theinsulating extension 53* (Figure 3) for connection to the plug connector28. For alternating current operation, particularly where the plungerand striker are to reciprocate synchronously, a circuit interrupter neednot be employed.

In the preferred forms of my invention I employ a permanent magnet tocoact with the plunger 5i to hold the striker 50 in the abovedescribedat-rest position wherein it is out of contact with the gong 45, and thispermanent magnet may or may not, as desired, coact with the magneticflux of the winding 55 in reciprocating the plunger 5|. An arrangementin which it does so coact will first be described, an arrangement inwhich the winding 55 is energized by alternating current to produce analternating 8 magnetic flux, with which the unidirectional flux of thepermanent magnet coacts to achieve synchronous reciprocation of theplunger and striker.

In this form, and referring first to Figure '7, I provide a permanentmagnet 12 in the form of a rectangular bar or block of highly retentivemagnetized material, such as Alnico, capable of producing a magneticflux that is relatively large in relation to that produced by thewinding for example, where the solenoid winding when energized byalternating current produces a peak magnetizing effect of about 850ampere turns, equivalent to about an average or mean value of 600 ampereturns, the permanent magnet may have a magnetizing effect on the orderof 1,400 ampere turns. The latter may be physically inter-related withthe plunger 5| and winding 55 in any suitable manner so that the twofluxes can suitably interact, being additive on one half-cycle ofenergization of the winding 55 and subtractive on the other half-cycle.Preferably 1 position the permanent magnet 12 on to one side of thewinding 55 and extend it by pole piece elements 73 and E4 to bring itsunidirectional flux to coact as just described. Pole pieces or poleextension 13, i4 are conveniently in the form of plate-like parts ofparamagnetic material, such as suitably heavy sheet steel, which may begiven the desired shape and configuration, as by punchpress operations.

As is better shown in Figure 7, the permanent magnet '12 rests againstthe plate support til, which is preferably of brass, off to one side ofthe large substantially rectangular hole 66 in the plate 60, and it isreceived between two upstanding lugs or ears and 69 formed integrallywith the plate support 66. In a direction lengthwise of the axis of thewinding 5 the magnet "a is of the same length as the winding unit53--555'!, so that these two parts are snugly received between the polepiece plates 53, "it, with the latter parallel to each other and atright angles to the axis of the bore of the winding unit; registeringwith this bore and of the same diameter are holes 13 and M in theextension poles l3 and 14, respectively. These have lugs or cars 13* andHirespectively, that rest against the plate support 60 to which they aresecured by screws #5, the end plates 73, M bridging across the opening59* in the plate 60 and overlying the longitudinal edges of the opening,thereby holding the winding unit in its above-described position inwhich it projects downwardly through the opening. These end plates alsohave lugs '13" and 14 which overlie the permanent magnet 12 Figures 6and '7) and the latter is thus securely held in place.

The relationship of the permanent magnet extension poles 13, 14 to thetubular casing part 63 and the plunger 5| in the latter is substantiallyas is better shown in Figure 6, wherein flux from the unidirectionalfield of the permanent magnet 72 flows in a magnetic circuit whichincludes the permanent magnet '12 and pole piece ?4, thence in a generalradial direction from the annular surfaces about the hole Hi to theplunger 5 I, thereby crossing a relatively small radial flux gaprepresented principally by the material of tubular casing part 36, thenfrom the inner or upper end of plunger 51 in a general axial directionalong a correspondingly axial flux gap to the annular surfaces at thehole 13, and then along the pole extension 73 and back to the permanentmagnet 12 the resultant pull exerted on the plunger 5! is resisted bythe spring 52 which, as a result, may be compressed and the resultantbalance of pull and spring forces holds the plunger in about theposition shown in Figure 6 and the striker 56 out of engagement with thegong 35. By means of the slots 56-65 and the screws iii58 (Figures 4, 6,and 7), the entire sub-assembly (of Figure '7) may be adjustablypositioned along the length of the tubular part 35, the latter extendingthrough the bore of the sub-assembly, and that includes the holes 13*and li of the pole piece extensions.

When the winding 55 is energized with alternating current, the fluxproduced thereby is in efiect superimposed upon the unidirectional fluxof the permanent magnet, in the above-described magnetic circuit. On onehalf-cycle the winding flux is in the same direction as the permanentmagnet flux, and the plunger 58 is forcibly drawn upwardly, furthercompressing the spring and tending to shorten the above-mentioned axialflux gap between the plunger and the pole piece '53; on the succeedinghalf-cycle the winding flux is in opposite direction, the magnetic pullon the plunger 5! is greatly reduced, and the energy stored in spring 52is thus released to snap the plunger 5! downwardly and cause striking ofthe gong 45, and upon the succeeding half-cycle, with the fluxes nowadditive, forcibly pull the plunger 5! upwardy to again compress thespring 52, these steps repeating themselves for so long as the circuitof winding 55 remains closed. The above-described adjustability of thesub-assembly along casing tube 36 may be utilized to achieve thatsetting which gives best ringing action, it being noted that thesubassembly, when secured in position by the screws 61, 68, forms ineffect a steadying support for the inwardly projecting tubular casingpart 36.

The arrangement just described utilizes both half-waves of theenergizing alternating current. Good efiects can be achieved, however,by unidirectionally energizing the winding 55, as with a succession ofunidirectional pulses. For ex ample, a single-wave rectifier might beincluded in the circuit of winding 55 so that the latter is energizedonly by half-waves of one sign of the energizing alternating current; insuch case the rectifier, which may be of any convenient form, such as aso-called copper-oxide-iron rectifier, may be included in theabove-described sub-assembly, as is shown in Figure 8, wherein such arectifier, generally indicated by the reference character 5'5, is showninsulatingly carried by a bracket It secured to the plate support 60 onone side of the winding unit, and in Figure 9 is diagrammatically shownhow the winding 55 and rectifier i! of such a sub-assembly are connectedin series across the connecting tabs 6!, 62 of the insulating plateextension 58 and from which conductors lead to the connecting plug 28.Where the power stroke of the plunger 5! is in response to energyreleased by the spring 52, as in the arrangement of Figure 6, thecircuit connections are so made that the half-waves or pulses utilizedto energize the winding 55 pass through the latter in a direction suchthat the corresponding flux produced in the above magnetic circuit is inthe same direction as that of the permanent magnet.

The arrangement of Figure 6 is of advantage where it is desired to use arelatively long coil spring 52, particularly one that has a nonlinearforce-deflection characteristic, as by giving it a tapered shape fromone end to the other, in order to substantially compensate for thenon-linear relationship between the magnetic force exerted on theplunger and the displacement of the plunger as the axial flux gapchanges, an arrangement that coacts in achieving synchronous plungeractuation. The above-described angular position of the re-entranttubular casing part it in relation to the interior of the sealedenclosure permits a substantial length of tubular part 35 to be nicelyaccommodated.

Under extremely adverse weather conditions it might be possible, inspite of the protective features above described, for the lower end ofthe striker 50 to become frozen against movement by ice or snow thatmight somehow accumulate or be formed, for example, in the angle betweenthe plane of theopen end of the tubular casing part 38 and the adjacentinside face of the portion 35 (Figure 6) of the gong Q5, and to combatsuch a condition I may re-arrange the structure of Figure 6 in themanner indicated in Figure 10. The paramagnetic plunger means within thereentrant casing part 36 may comprise a multi-part plunger structurewith the parts coacting with each other and with the permanent magnetfield and the field of the winding so as to partake of substantiallyconjoint mo tion or reciprocation as a unit under certain conditions andto partake of substantial relative axial movement when the striker 50 isimmobilized, as by an ice formation. Illustratively, for one part, I mayuse the plunger 55, as in Figure 5, with which the striker ismechanically connected, and for the other part a somewhat shorter pluner 5l above the plunger 5! and axially spaced from the latter by acoiled spring 52 preferably of non-magnetic material, such as brass orPhosphor bronze, and inside of which there extends downwardly a stem 5?,preferably of non-magnetic material, secured at its upper end to theupper plunger 5!". Plunger 5! b may be of chromium-plated soft iron.Between the upper end of the latter and the sealed inner end of tubularcasing 36 is interposed a coiled spring 52 which, according tocircumstances, may have a non-linear characteristic, if desired.

The several parts are so proportioned that, with the plunger 5! heldretracted by the force of the permanent magnet flux, thus holding thestriker 5!? out of direct contact with gong 45, spring 52 which, likespring 52*, may be under some strain in this at-rest position-holds theupper plunger 5! more or less out of the axial flux gap between theupper end of plunger 5! and the annular surfaces about the hole '13 inthe extension pole 73, and in that position the lower end of the shortstem 5! is spaced axially away from plunger 5i.

When the winding 55 is energized, as herein described, so that its fluxis added to that of the permanent magnet along the above-mentioned axialflux gap, the plungers 5! and 51 move upwardly under the pull exerted onthe plunger 5!, compressing both springs 52 and 52 and during thisaction, if the stem 5! is engaged by the lower plunger 5!, the lattercan thereby directly increase the compression of the upper spring 52 andthe energy stored therein. When the winding flux changes, as abovedescribed, to effect a downward stroke of movement of the striker 58,the plunger system is snapped or projected downwardly at substantialvelocity as the energy in the two springs is thus released, and duringthis action some relative axial movement between the plunger parts 5iand 5H may take place under the action of spring 52 The pull 11 of thepermanent magnet flux, upon conclusion of the downward stroke, restoresthe parts to the at-rest position above described.

However, should the striker 59 be frozen or otherwise immobilized, axialmovement oi plunger under the control of the winding flux, does not takeplace and the inner end face of plunger 5! now becomes a flux-guidingface for flux of both permanent magnet and of the winding in an axialfiux gap reaching toward the lower end face of plunger Bi and to theannular surfaces about the hole 13 in pole piece is, exerting a powerfulpull on the plunger 5 i to snap it downwardly toward the plunger 5!,aided somewhat by the spring 52 the pull increasing very rapidly as thisfluxgap shortens; as a result, spring 52 yields and the stem 5!" ispowerfully impacted against the plunger iii, the force of the impactbeing transmitted to the end of striker 5G to fracture any ice formationat that end. Rounding over or tapering the end of striker 59 is of aidas it acts like a wedge driven into the ice formation. When theenergization of winding 55 is such as to diminish the magnetic flux inthe now shortened air gap between the two plunger parts, the energystored in spring 52 forces the plunger 5! upwardly toward its at-restposition, as suggested in Figure 10, thus completing one cycle of anice-breaking stroke with the resultant retractile stroke for the plunger55 relative to the striker 50.

It will now be clear that these cycles are repeated at great rapidity,particularly if the winding is energized with alternating current atsuit able frequency, usually 60 cycles, the actuation of the ice-breakerplunger 5t being substantially synchronous therewith. Fragmentation andclearing of the ice formation results in freeing the striker 53 formovement, whereupon continued energization of the winding 55 achievesreciprocation of the system and striker st for sounding the gong, in themanner first above described.

The spring and plunger in Figures 6 and 10 are well protected againstforeign matter and effects of weather and the like; nevertheless, itmight be desired under some circrm'lstancesto eliminate use of a spring.With the gong 45 outside of the sealed casing and desirably detachablysecured thereto as above described, when position it serves to preventremoval of the plunger-striker unit and of the spring, these in effectbeing external of the sealed enclosure. In Figures 11 and 12 I haveshown a form of my invention which has the advantages of assembly andoperation without such a spring.

I again employ a sub-assembly that is sleeved onto the inner closed endof the casing tube 36, as before, and it again comprises a plate support68 having a bar or block type of permanent magnet '52 at one end, heldin place by lugs Bil and $6 upstanding from the plate 66 and byoverlying lugs 73 and 14 of the plate-like pole extensions T3 and Mwhich are secured by lugs and screws to the support 60 as before.Preferably the permanent magnet 12 is somewhat longer and the spacingbetween the plate pole extensions :3 and Hi correspondingly larger inorder to accommodate therebetween two windings 55 and 55 with aparamagnetic plate-like intermediate pole extension 83 (Figures 11 and12) the intermediate pole piece 83 bridges across the plate opening 6Band its right-hand edge, as seen in Figure 12, abuts flatwise againstthe adjacent face of the permanent magnet 12 so as to be in goodflux-conductive contact therewith. Intermediate pole piece 83 has around hole 3*- therein, and the winding unit and sub-assembly can thusbe sleeved onto the inner closed end of the casing tube 36 as shown inFigure 11 and adjustably secured by the screw and slot connection to theinternal brackets 63 and 65. It is fixed in a position such that theflux from the permanent magnet 12 holds the plunger 5| (Figure 11) inthe desired position with the striker 5Q appropriately spaced from thegong 45.

Plunger 5! is of a length shorter than the spacing between the endmostpole extensions i3 and 14, thus providing, when in mid-position,generally axial flux gaps between its ends and the respectively adjacentbut spaced pole pieces 13 and 14, with about the central portion ofplunger 5| surrounded by the intermediate pole pieces 33, being spacedtherefrom by an annular radial flux gap of relatively small dimension,on the order of the thickness of the wall of the casing tube 36. Alongthese axial flux gaps, flux from the permanent magnet 72 can exertforces on the plunger 5| and these, when affected by the energization ofthe windings 55 and 55", illustratively in a manner later described, caneffect synchronous reciprocation of the plunger and striker andcorrespondingly impact the gong synchronously.

To hold the striker 50 in an at-rest position out of engagement with thegong against the effect of the Weight on plunger and striker tending toslide them downwardly in Figure 11, I may utilize a relationship ofparts as is there indicated; this includes giving the striker rod 58such a length that when its end engages the gong 45, the plunger 5| isin a position where the axial flux gap between its upper end and polepiece 13 is shorter than the axial iiux gap be tween its lower end andthe pole piece i l. Accordingly, permanent magnet flux in the mag neticcircuit comprising the permanent magnet 12, pole piece 13, upper axialflux gap, piling 5i, intermediate pole 83, and back to the manent magnet12, is greater than the permanent magnetic flux in the magnetic circuitcomprising permanent magnet 12, intermediate pole piece 83, plunger 5|,lower axial flux gap, pole piece M, and back to the permanent magnet'52, and accordingly the pull on the plunger Si is greater in an upwarddirection and plunger and striker rod are moved into and held in anatrest position somewhat as shown in Figure 11, in which the plunger 5|has its axial mid-point substantially coincident with the central planebetween the parallel pole pieces T3 and 83. Actually the plunger 5! isdisplaced a little bit downwardly from that point of coincidence becauseof the weight of the movable parts and because of the effect of axialpull downwardly by flux along the lower axial flux gap between the lowerend of plunger 5| and the lower pole piece 14. This latter pull ismaterially diminished because that axial fiux gap is of materiallygreater length. This at-rest position is dependably maintained and inthis arrangement the striker rod cannot be held constantly in contactwith the gong 45 because that contact prevents the lower axial flux gapfrom ever becoming shorter than the upper axial flux gap, as earlierexplained.

Windings and 55 are connected in series, as shown in Figure 13, acrossthe connecting tabs 68 and 52 carried by the insulating plate 53, theserial connection being such that the windings produce magneto-motiveforces and resultant axial flux in opposite directions. When energizedby alternating current, on one halfwave winding 55 produces magneticflux in the upper magnetic circuit, as viewed in Figure 11, in adirection opposed to the permanent magnet flux in that circuit andwinding 55 produces magnetic flux in the lower magnetic circuit in thesame direction as that produced therein by the permanent magnet;accordingly the flux in the lower axial flux gap is greatly increased(in the magnetic circuit comprising the lower part of permanent magnet72, intermediate pole piece 33, lower part of plunger axial flux gap,lower pole piece H, and back to the permanent magnet 52) with the resultthat the plunger and striker are snapped downwardly with substantialvelocity and energy. In this manner the plunger and striker are movedout of their at-rest position and at about the moment of impact thelower axial flux gap is exceedingly small, whereas the upper axial fluxgap is now of substantial length. On the next and reversed half-wave,the flux of upper winding 55 is in the same direction across the upperflux gap as is the permanent magnet flux, in the upper magnetic circuit,and the flux from the lower winding 55 is in a direction opposing thepermanent magnet flux across the lower axial flux gap, in the lowermagnetic circuit, whereupon the plunger and striker are snappedupwardly, whereupon the succeeding half-wave sheets a downward stroke ofmovement, these actions and steps following in synchronous successionfor so long as the circuit of the two windings is maintained closed.

When the circuit is open and the two windings deenergized, the plungerand striker are pulled and held into the atest position indicated inFigure 11 and as above described.

The adjustable setting of the winding and permanent magnet sub-assembly(as seen in Figure l2) lengthwise of the re-entrant casing tube 35 alongthe supporting brackets 63 and 84 is of advantage not only in assemblyof the structure in course of manufacture, but also in empirically orduring testing speedily achieving the coacting relation hips abovedescribed.

If desired, instead of using a single elongated bar type of magnet 72 asin Figure 12, two smaller or shorter permanent magnet blocks may beemployed as shown at W and 12 in Figure 14, and in such case theintermediate pole piece can be extended to reach inbetween the twomagnets 72 and '32 If the latter are arranged so that the north pole ofmagnet 72 engages pole piece it and the south pole of magnet 52 engagespole piece is, the windings 55 and 55 are again connected to produceflux in opposite directions. On the other hand, if one of the magnets 12or la is reversed end for end, so as to reverse the direction of iiow ofpermanent magnet flux in its magnetic circuit, the windings 55 and 55'are connected to produce fluxes in the same direction. In either casethe operation will now be clear in view of the description of theembodiment of Figures 11 and 12.

In these forms the flux-responsive structure for actuating the striker55 may also be arranged to achieve ice-breaking action to free thestriker in in it becomes immobilized by freezing, and this may be doneby providing a coacting paramagnetic plunger til as indicated in Figure11 and shown on a larger scale in Figure 11a; in this form the plungerfil which may be of soft iron chromium-plated, has a central or axialbore therethrough so that it may be sleeved onto the striker rod 56 forease of axial movement relative thereto, striker rod being preferablymade of any suitable non-magnetic material. Extending about the strikerrod 50 and between the lower end of plunger 5| and the upper end ofplunger til is a coiled spring 52 of such a strength and so dimensionedthat, with the mov ing parts held in the at-rest position abovedescribed, the upper end of plunger 5| just about enters the opening 14in the extension pole piece it, a collar 8'5 secured to the striker rod56 limiting downward movement of plunger 5W along the rod 53, as isbetter shown in Figure 11a.

When the windings and 55 are energized as above described, the plunger5| and striker 5B reciprocate as before, carrying plunger 51 along withit, and during the strokes of reciprocation little, if any, materialrelative axial movement between the plunger fil and plunger 5i need takeplace, plunger 51 barely, if at all materially, entering the axial fluxgap between the pole pieces 74 and 83.

However, if striker rod 55 is immobilized, thus holding plunger 5!against movement out of its at-rest position, energization of winding 55in a direction to add to the permanent magnet flux in the axial flux gapthat extends downwardly from the lower end of plunger 5! to the upperend face of plunger 51*, exerts a powerful upward pull on plunger 5 I apull which increases rapidly as the axial gap is shortened by upwardmovement of the plunger 51 thus compressing spring 52 and storingsubstantial energy in it; when the energization of the winding thenchanges to diminish the flux in the shortened axial flux gap, the energystored in spring 52 is released and the plunger di is snapped downwardlyat substantial velocity, its kinetic energy, when its downward movementis suddenly halted by the collar 86, being transmitted to the strikerrod 59 to fragment or crush the ice accumulation or other cause thatimmobilizes the striker 53. Under the control of the winding flux, suchreciprocation relative to the striker rod 5t and plunger 55 can berepeated in rapid succession, synchronously where the energization is bype riodic or successive current pulses, and once striker 50 is freed, soas to release plunger 5i for reciprocation, the latter partakes ofcontrolled reciprocation as before with plunger 5! moving along with itsubstantially as earlier described above.

In Figures 15 and 16 I have shown a winding 55 wound or mounted on asuitable insulating form or spool and provided with insulating endplates 5! and 58, as before, and assembled to the plate support 66 bymetal end plates 87 and 38 secured by suitable ears and screws ?5. Endplate 88 is of paramagnetic material, and adjacent one end thereof it isin fiatwise flux-conductive engagement with a small block-like permanentmagnet 90 Whose opposite end face is in similar flux-conductiveengagement with a companion paramagnetic plate member shaped substan'tially the same as plate 88 and being provided with ears or lugs throughwhich pass screws t2 securing it to the plate support 59 and holding itparallel to the companion plate 88.

Permanent magnet block as rests against the plate support 58 betweenupstanding lugs and 65 and is further held against dislocation byoverlying lugs Qi and 83 of the metal plates.

The winding unit 58-55-51 has a central channel or bore therethrough, asbefore, and the 15 parallel plates 81, 88, and 9| are provided withaligned circular apertures 81 88 and m which are aligned with thecylindrical bore of the winding unit, all or them being of a diameter sothat the sub-assembly as seen in Figure 16 can be sleeved, or slid ontothe internally projecting tubular casing part 35, as shown in Figuure15, screws 6? and 58 securing the sub-assembly to the inclined brackets53 and 64, adjustably by way of the slots 55 and 66.

The tubular casing part 36 again contains a plunger i and striker rod50, and in the form shown the plunger 5|, in its at-rest position, islocated with its magnetic center displaced upwardly to the right of themagnetic center of the solenoid winding. 55 so that upon energization ofthe latter, plunger 5| is drawn downwardly to impact striker 50 againstthe gong 45.

Intermediate of its ends, striker rod 55 carries a paramagnetic plunger5i, which may be of chromium-plated soft iron, for coaction with thepermanent magnet flux to which it is subjected by the extension poles 88and 9! which, like the other extension poles above described, surroundthe tubular part 36; these parts coact to hold the striker 50 in anat-rest position where it is out of contact with the gong 45 and to givethe plunger 5! and striker 50 a return or reverse stroke of movement atthe conclusion of each power stroke eflected by the magnetic force ofwinding 55 on the part 5|.

The plunger 5 l is of a length in relation to the axial dimension of thepermanent magnet circuit substantially as indicated in Figure 15, andpermanent magnet fiux flowing axially in the plunger 5P tends to forceand hold the plunger 5& with its mid-point substantially coincident witha mid-plane between the pole pieces 88 and 51. When winding 55 is givenan energizing pulse, plunger 5| is forced downwardly to the left inFigure 15 to impact the striker 50 against the gong 45 and in the courseof that stroke of movement, plunger or core 5| opens up, increasingly inaxial direction, what is in eifect an axial flux gap between the upperend of plunger 5! and the flux guiding surfaces about the hole 58* inthe pole piece 88, thus rapidly diminishing, at e. rapidly increasingrate, the pull or holding action of the permanent magnet flux on theplunger 5H and hence upon the moving parts; this means that the forceopposing the magnetic iorce exerted by winding 55 on part 5! rapidlydiminishes so that the rapidly increasing magnetic force of winding 55on part 5!, effected not only by a rise in instantaneous current valuein the winding 55 but also by the square law solenoid eifect, can causethe striker 56 to impact the gong 45 at high velocity and energy. Uponsubstantial collapse of the pulse of energizing current in winding 55,with resulting substantial collapse of the magnetic field produced bythe winding 55, the flux of permanent magnet 55, flowing from pole piece88 in general axial direction to the upper end of core 51, across thethen relatively long axial flux gap, snaps the core 5% and the partsconnected to it upwardly to the ri ht in Figure 15 to restore it to itsat-rest position or to permit repetition of the justdescribed cycle ofoperation upon the ensuing pulse of energization of winding 55.

During gong striking stroke and the ensuing stroke of the moving parts,the effectiveness of change in the axial flux gap between core 5W andpole piece 88* is maintained by the substantial invariability of theannular radial flux gap between the concentric surfaces of the hole Slin the pole piece 9| and the cylindrical surface of core 5W, that radialflux gap being of relatively small dimension. However, any desiredcharacteristic of change in magnetic force on the core 5| in relation toaxial displacement of the core 55 may be achieved by appropriatelyshaping the coacting flux guiding faces of the parts. For example, ahigher rate of change in reluctance of the flux gaps in the magneticcircuit of the permanent magnet 90 may be effected as by appropriatelychanging the radii of the external surface of the core 5W, as isindicated in the fragmentary view of Figure 17 where an intermediateportion of core 5W is tapered, as indicated at 93, so that when thetapered portion, on downward movement of core 5H, comes more and moreinto juxtaposition to the flux face 55' of pole piece 9i, that radialflux gap is increased in effective radial dimension and its reluctancecorrespondingly increased.

In any case, the parts are so proportioned and the winding unitsub-assembly so adjusted lengthwise of the casing tube 35 that gong (seeFigure 15) coacts with the permanent magnet circuit in that it preventsthe core 5H from such excessive axial movement as would bring t out ofthe desired coacting relation with the permanent magnet circuit foreffecting a return stroke of movement.

Winding may be energized in any suitable manner as will now be clear,with an appropriate energizing impulse or succession of pulses ofcurrent. Illustratively, but not by way of limitation, it may beenergized from a direct current source with the aid of a suitablecircuit interrupter which may be of any suitable type and may be relatedin any suitable manner to the magnetic field produced by winding and inFigure 16 anillustrative vibrating form of interrupter is shown andgenerally indicated by the reference character 95.

ihe interrupter may comprise a flat leaf spring 55 insulatinglysupported in any suitable manner, as indicated at 91, from one end edgeof the pole piece plate 88, its extreme end portion 55* being providedwith suitable means for connecting an electric conductor thereto.- Leafspring 56, preferably of steel, has secured to it, as by riveting, asoft iron plate-like armature 98 which terminates in juxtaposition tothe vertical end edge face, as seen in Figure 16, of the winding unitend plate 81 which is made of sheet steel or the like. Accordingly parts88, 96, 98, and 8'! form a magnetic circuit for flux produced by thewinding 55, so that upon energization of winding 55 armature 98 isattracted and moved toward the part 81, lessening the flux gaptherebetween. This movement ofv armature 98 is utilized to break thecircuit of winding 55, and this may be done by a contact element 99carried at the free and somewhat bent end of flat spring 96 andnormally, under the action of spring 95, held in engagement with anadjustable stationary con.- tact which can be in the form of a contactscrew H15 carried in a bracket 10! which is insula tingly supported inany suitable manner on the plate support and which is provided with abinding screw N12 for connecting the conductor thereto. By setting screwI00 against the bias of spring 95, the normal at-rest dimension of theflux gap between parts 98 and 81 may be adjusted to give the desiredfrequency of vibration and hence fre-- quency of circuit interruptionand of energizing pulses for the winding 55. In Figure 18 is dia- 17grammatically shown the series connection of the winding 55 andinterrupter 95 across the connector tabs 6! and 82 carried by theinsulating plate 58 of the winding unit.

The various adjustments described can be empirically arrived at incourse of assembly or test and before the mechanism becomes sealedwithin the casing 2il2l36; with the interrupter also enclosed, thedevice may be safely used in atmospheres where there is risk ofexplosive content, any sparking at the interrupter contacts being thusrendered harmless. that in place of the interrupter 95, the sub assemblyof Figure 16 may have mounted on it a rectifier like the rectifier i! ofFigure 8 where impulse energization of that kind from an alternatingcurrent source may be desired, in which case the circuit arrangement isas shown in Figure 9; also, the interrupter arrangement shown in Figure16 is intended to be illustrative of how an interrupter may be employedin not only the forms of Figures 15 and 17, but also in any other form,for example, that of Figures 8 and 10 where impulse energization in thatmanner is desired.

In Figure 17 I have shown the embodiment of Figure 15 arranged forice-breaking action, and there I have arranged the paramagnetic plungerparts 5! and 51 for relative axial movement, in that striker 59 ismechanically connected to plunger 5% and plunger 5! is provided with adownwardly extending stem El preferably of non-magnetic material, beingsurrounded by a spring 52 which is interposed between the two plungersand normally holds them apart so that stem 5i is spaced from the upperend of plunger 51, somewhat as in the arrangement of Figure preferably ashort cushioning spring 52 is interposed between the sleeved inner endof tubular casing 36 and the upper end of plunger 5F.

The at rest position of the parts is substantially as shown in Figure17, being so held by the action of the permanent magnet flux on theplunger 5H. Should striker 5:; be immobilized, as by an accumulation ofice as above noted, the plunger 51 remains stationary upon subsequentimpulse energization of the winding 55 and the flux of the latter,produced internally and coaxially of the tubular part 38 that is withinthe winding 55, exerts a strong pull in downward direction on theplunger 5! and in effect snaps the latter downwardly at substantialvelocity and against the action of spring 52 which can be of relativelysmall strength, to impact the stem 58 against the plunger 55 and by theenergy of the resultant blow driving the striker 56 into the iceformation; when the energizing impulse ceases or diminishes, the spring52 moves the plunger 5! upwardly to position it to be again snappeddownwardly upon the succeeding impulse energization of the winding 55 torepeat the cycle.

Such cyclic reciprocation is rapidly repeated as the impulseenergization of the winding continues and when the striker 5-3 is freed,both plungers 5! and 5 i can partake of axial reciprocation somewhat asa unit, though in the course of the downward or power stroke, relativeaxial movement between them can take place in that, depending uponcorrelation of strength of spring 52 to other factors, downward movementof plunger 5! can take place at high enough velocity to impact againstthe plunger 51* before the eiiect of its inertia and the eiiect of thepermanent magnet pull thereon are overcome by the It will be understoodcompression of the spring 52 in which case the striker 50 is suddenlyimpelled downwardly at good velocity to effect striking of the gong bythe striker 50; when the current impulse energizing the winding 55ceases or is sufficiently diminished, the permanent magnet flux, aidedby some rebound of the striker 50, pulls the parts upwardly tosubstantially the at-rest position, at which moment the succeedingimpulse of energizing current becomes operative upon the plunger systemto repeat the cycle where repeated or substantial synchronous strikingof the gong is desired. During these actions the spring 52 desirablyserves yieldingly to limit the retrograde stroke of plunger 5|appropriately, and it can also act to prevent the plunger from actuallystriking closed end of the tubular casing part 36.

The construction in its illustrative embodiments will be seen to havenumerous advantages from many viewpoints, such as manufacture, assembly,adjustment or testing, installation, and repair or replacement of parts.For example, a setting of internally adjustable parts once made and thestructure assembled and sealed, cannot bet detrimentally disturbed byshift or displacement of the gong which cannot be rotativelydisplacednor can it be removed and put back in other than its initial position.

Moreover, it will be seen that the invention provides a signallingdevice in which the various objects above set forth and also elsewhereindicated are successively achieved; the construction will be seen to berugged and dependable, particularly under widely varying conditions ofpractical use, and particularly under adverse weather conditions such asare met with on shipboard, for example.

As many possible embodiments may be made of the above invention and asmany changes might be made in the embodiments above set forth, it is tobe understood that all matter hereinbefore set forth or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

I claim:

1. A weatherproof and de-icing signalling construction comprising meansforming a sealed casing having an opening in a wall thereof from which are-entrant tube-like casing part extends upwardly and inwardly into thecasing to form an air trap against the rise of water thereinto, a gongsupported externally of said casing with a portion thereof adjacent saidopening, a striker in said re-entrant casing part and reciprocablethrough said opening for striking said gong, paramagnetic means withinsaid re-entrant casing part and protected against water by said air trapand reciprocably movable therein in strokes toward and away from saidopening, said paramagnetic means comprising a plurality of paramagneticplungers having means mechanically interrelating them for movement inthe same direction on each stroke and for movement of one relative tothe other, one of said paramagnetic plungers having mechanicalconnection with said striker whereby the latter is reciprocated intostriking engagement with said gong upon movement of said plungers insaid strokes and whereby, when said striker is immobilized by icing atits outer end and thereby the plunger connected to it is alsoimmobilized, the other of said plungers may partake of movement towardand away therefrom, and magnetic fluxproducing means controllingactuation of said paramagnetic plungers and including electromagneticwinding means within said sealed casing and coacting upon energizationto reciprocate both plungers to effect striking of said gong by saidstriker and, upon immobilization of said one plunger by icing of thestriker, to reciprocate the other plunger relative thereto to dissipateits kinetic energy thereon through said striker to free itself from theicing.

2. A weatherproof and de-icing signalling construction as claimed inclaim 1 in which said magnetic flux-producing means includes alsopermanent magnet means the flux of which acts upon said plunger that ismechanically connected to the striker to hold it and the striker, duringde-energization of said winding means, in retracted position and inwhich the flux produced by said winding means, when energized, acts uponthe other plunger.

3. A weatherproof and de-icing signalling construction as claimed. inclaim 1 in which said magnetic flux-producing means includes alsopermanent magnet means the flux of which acts upon said plunger that ismechanically connected to the striker to hold it and the striker, duringde-energization of said winding means, in retracted position and inwhich the other plunger surrounds and is slidable relative to thestriker for reciprocation therealong toward and away from saidstriker-connected plunger and the flux produced by said winding means,when energized, acting upon the latter to effect striking reciprocationof the striker and, upon immobilization thereof, acts through saidstriker-connected plunger upon the other to reciprocate the latterrelative to the former along said striker.

4. A weatherproof and de-icing signalling construction as claimed inclaim 1 in which said magnetic flux-producing means includes alsopermanent magnet means the flux of which acts upon said plunger that ismechanically connected to the striker to hold it and the striker, duringde-energization of said winding means, in retracted position and inwhich the other plunger is interposed between said striker-connectedplunger and the inner end of said re entrant casing part forreciprocating movement toward and away from said striker-connectedplunger, the flux of said winding means, when energized, acting upon thelatter for striking r reciprocation of said striker and, uponimmobilization thereof, acting upon said other plunger to reciprocate itinto impacting engagement with said striker-connected plunger.

5. In a signalling construction, in combination, means forming a sealedcasing having a substantially vertical wall externally of which ismounted a gong, said wall having an opening adjacent a part of the gongto be struck and a reentrant tube-like casing part extending from saidopening inwardly and upwardly into the in- .terior of the sealed casingand forming an air trap to prevent rise of water thereinto, aparamagnetic plunger slidable in said tube-like casing part andprotected against water by said air trap, said plunger having strikermeans operating upon said gong portion through said opening, means forholding said striker means in an at-rest position out of contact withsaid gong to prevent water accumulation and freezing thereat and foractuating said plunger to cause striking of said gongcomprisingpermanent magnet means producing a magnetic field the flux ofwhich exerts a magnetic force on said plunger H to hold it and saidstriker means against descent 20 in said tube-like casing part, andelectro-mag netic winding means within said sealed casing and extendingabout said tube-like casing part to produce a magnetic field, whenenergized, the flux of which acts upon said plunger through the walls ofsaid tube-like casing part.

6. In a signalling construction, in combination, means forming a sealedcasing having a substantially vertical wall externally oi which ismounted a gong, said wall having an opening adjacent a part of the gongto be struck and a re-entrant tube-like casing part extending from saidopening inwardly and upwardly into the interior of the sealed casing andforming an air trap to prevent rise of water thereinto, a paramagneticplunger slidable in said tube-like casing part and protected againstwater by said air trap, said plunger having striker means operating uponsaid gong portion through said opening, means for holding said strikermeans in an at-rest position out of contact with said gong to preventwater accumulation and freezing thereat and for actuating said plungerto cause striking of said gong comprising spring means in said tube-likecasing part and interposed between the inner end thereof and saidplunger for impelling the plunger and striker means downwardly to strikesaid gong, permanent magnet means exerting upward force on said plungerand partially compress said spring means to hold said plunger in aposition with the striker means out of contact with said gong, and anelectro-magnetic winding about said re--entrant tube-like casing partand producing, when energized by current pulses of one sign, a magneticfield for each pulse in a direction additive to that of said permanentmagnet means and thereby further compress said spring means during eachof said energizing pulses.

7. In a signalling construction, in combination, means forming a sealedcasing having a substantially vertical wall externally of which ismounted a gong, said wall having an opening adjacent a part of the gongto be struck and a re-entrant tube-like casing part extending from saidopening inwardly and upwardly into the interior of the sealed casing andforming an air trap to prevent rise or water thereinto, a paramagneticplunger slidable in said tube-like casing part and protected againstwater by said air trap, said plunger having striker means operating uponsaid gong portion through said opening, means for holding said strikermeans in an at-rest position out of contact with said gong to preventwater accumulation and freezing thereat and for actuating said piungerto cause striking of said gong comprising permanent magnet means withinsaid sealed casing and having spaced pole extensions related to thewalls of said "re-entrant tube-like casing part to direct unidirectionalmagnetic fiux thercthrougli for action upon said plunger to hold it andsaid striker means against descent into engagement with said gong, andmeans comp ising an electro-rnagnetic winding within said sealed casingto produce a magnetic field, when energized, coacting to project saidplunger and striker means downwardly.

8. In a signalling construction, in combination, means forming a sealedcasing having a substantially vertical wall externally of which ismounted a gong, said wall having an opening adjacent a part of the gongto be struck and a reentrant tube-like casing part extending from saidopening inwardly and upwardly into the interior of the sealed casing andforming an air trap to prevent rise of water thereinto, a paramagneticplunger slidable in said tube-like casing part and protected againstwater by said air trap, said plunger having striker means operating uponsaid gong portion through said opening, means for holding said strikermeans in an at-rest position out of contact with said gong to preventwater accumulation and freezing thereat and for actuating said. plungerto cause striking of said gong comprising permanent magnet means withinsaid sealed casing and having pole extensions axially spaced relative tothe axis of said re-entrant tube-like casing part to produceunidirectional magnetic flux within said re-entrant casing part, saidplunger having two parts, one of which is acted upon by said flux tohold it and said striker means against descent into engagement with saidgong, and an electro-magnetic winding within said sealed casing andproducing, when energized, a magnetic field acting through the walls ofsaid re-entrant tube-like casing part and upon the other part of saidplunger.

9. In a signalling construction, in combination, means forming a sealedcasing having a substantially vertical wall externally of which ismounted a gong, said wall having an opening adjacent a part of the gongto be struck and a re-entrant tube-like casing part extending from saidopening inwardly and upwardly into the interior of the sealed casing andforming an air trap to prevent rise of water thereinto, a paramagneticplunger slidacle in said tube-like casing part and protected againstwater by said air trap, said plunger having striker means operating uponsaid gong portion through said opening, means for holding said strikermeans in an at-rest position out of contact with said gong to preventwater accumulation and freezing thereat and for actuating said plungerto cause striking of said gong comprising permanent magnet means withinsaid sealed casing and having two pole extensions spaced along the axisof said re-entrant tube-like casing part to produce through the wallsand within the latter unidirectional magnetic flux along the axial fluxgap between said spaced pole extensions and into which axial flux gapthe upper portion of said plunger extends, said gong acting through saidstriker means to prevent descent of said plunger completely out of saidaxial flux gap whereby the pull of said flux on said plunger returns andholds said striker means out of engagement with said gong, andelectro-magnetic winding means within said sealed casing and coacting toproject said plunger and striker downwardly.

10. In a signalling construction, in combination, means forming a sealedcasing having a sub stantially vertical wall externally of which ismounted a gong, said wall having an opening adjacent a part of the gongto be struck and a reentrant tube-like casing part extending from saidopening inwardly and upwardly into the interior of the sealed casing andforming an air trap to prevent rise of water thereinto, a paramagneticplunger slidable in said tube-like casing part and protected againstwater by said air trap, said plunger having striker means operating uponsaid gong portion through said opening, means for holding said strikermeans in an at-rest position out of contact with said gong to preventwater accumulation and freezing thereat and for actuating said plungerto cause striking of said gong comprising permanent magnet means withinsaid sealed casing and having a plurality of axially spaced poleextensions along said re-entrant tubelike casing part between two ofwhich is formed one axial flux gap andtwo of which form a second axialflux gap, for flux from said permanent magnet means, said twoaxial fluxgaps being substantially axially aligned for flux conduction within saidtube-like casing part for coaction with said plunger whereby themagnetic forces exerted axially on said plunger tend to force it tosubstantially bridge one or the other of said axial flux gaps, andelectro-magnetic winding means in said sealed casing and coaxial withsaid re-entrant tube-like casing part for affecting the relative eifectsof the permanent magnet fluxes in said two flux gaps and thereby effectmovement of said plunger and striker means.

11. In a signalling construction, in combination, means forming a sealedcasing having a substantially vertical wall externally of which ismounted a gong, said wall having an opening adjacent a part of the songto be struck and a reentrant tube-like casing part extending from saidopening inwardly and upwardly into the interior of the sealed casing andforming an air trap to prevent rise of water thereinto, a paramagneticplunger slidable in said tube-like casing part and protected againstwater in said trap, said plunger having striker means operating uponsaid gong portion through said opening, means for holding said st ikermeans in an at-rest position out of contact with said gong to preventwater accumulation and freezing thereat and for actuating said plungerto cause striking of said gong comprising permanent magnet means withinsaid sealed casing and having three pole extensions axially spaced alongsaid re-entrant tube-like casing part and thereby providing two axiallyaligned flux gaps within said tube-like casing part for coaction withsaid plunger, whereby said plunger tends to assume a position in whichit substantially bridges one of said axial flux gaps or the other, andelectro-magnetic winding means within said sealed casing eifective, whenenergized, to alternately change the effective fiux values in said twoaxial flux gaps and thereby effect reciprocation of said plunger andstriker means.

12. In a signalling construction, in combination, means forming a sealedcasing having a substantially vertical wall externally of which ismounted a gong, said Wall having an opening adjacent a part of the gongto be struck and a reentrant tube-like casing part extending from saidopening inwardly and upwardly into the interior of the sealed casing andforming an air trap to prevent rise of water thereinto, a paramagneticplunger slidable in said tube-like casing part and protected againstwater in said air trap, said plunger having striker means operating uponsaid gong portion through said opening, means for holding said strikermeans in an at-rest position out of contact with said gong to preventwater accumulation and freezin thereat and for actu ating said plungerto cause striking of said gong comprising permanent magnet means withinsaid sealed casing and having three pole extensions axially spaced alongsaid re-entrant tube-like casing part and thereby providing two axiallyaligned flux gaps within said tube-like casing part for coaction withsaid plunger, whereby said plunger tends to assume a position in whichit substantially bridges one of said axial flux gaps or substantiallybridges one of said axial flux gaps or the other, stop means to preventdownward movement of said plunger beyond that point at which the lowerof said two axial flux gaps is effective to hold the plunger against theupward pull of the flux in the upper flux gap, and electromagneticwinding means within-saidsealed casing which, when energized, overcomesthe holding force of the upper flux gap on said plunger and therebycontrols descent thereof to strike said gong with said striker means.

13. In a signallin construction, in combination, means forming a sealedcasing having a substantially vertical wall externally of which ismounted a gong, said wall havin an opening adjacent a part of the gongto be struck and a reentrant tube-like casing partextending from saidopening inwardly and upwardly into the interior of the sealed casing andforming an air trap to prevent rise of water 'thereinto, a paramagneticplunger slidable in said tube-like casin part and protected againstwater .in said air trap, said plunger having striker means operatingupon said gon portion through said opening, means for holding saidstriker means in an at-rest position out of contact with said gong toprevent water accumulation and freezing .thereat and for actuating saidplunger to causestriking of said gong comprising permanent magnet meanswithin said sealed casing and having three pole extensions axiallyspaced along said re-entrant tube-like casing part and thereby providingtwo axially aligned flux gaps within said tube-like casing part forcoaction with said plunger, whereby said plunger tends to assume aposition in which it substantially bridges one of said axial flux gapsor the other, stop means to prevent downward movement of said plungerbeyond that point at which the lower of said two axial flux gaps iseffective to hold the plunger against the upward pull of the flux in theupper flux gap, and electromagnetic winding means within said sealedcasing and coacting, when energized, to oppose the permanent magnet fluxin said upper flux gap and to aid the permanent magnet flux in the lowerof said axial flux gaps and thereby effect descent of said plunger andstriking of said gong with said striker means.

14. In a signalling construction, in combination, means forming a sealedcasing having a'substantially vertical wall externally of which ismounted a gong, said wall having an opening adjacent a. part of the gongto be struck and a reentrant tube-like casing part extending from saidopening inwardly and upwardly into the interior of the sealed casing andformin an air trap to prevent rise of water thereinto, a paramagneticplunger slidable in said-tube like casing part and protected againstwater by said air trap, said plunger having striker means operating uponsaid gong portion through said opening, means for holding said strikermeans in an at-rest positicn out of contact with said gong to preventwater accumulation and freezing thereat and for actuatin said plunger tocause striking of said gong comprising permanent magnet means-withinsaid sealed casing and having pole extensions axially spaced relative tothe axis of said reentrant tube-like casing part, one of which poleextensions comprising an axially extending part to produce between thelatter and another of said pole extensions a unidirectional magneticflux within said re-entrant casing part that acts upon said plunger tohold it and said striker means against descent into engagement with saidgong, and an electro-niagnetic winding coaxial with said re-entranttube-like casing part and said pole extension part and by itsmagneto-motive .force alter the holding forceoi the permanent 24 magnetflux on-said plunger and cause movement of the latter-and said strikermeans.

15. In a signalling construction, in combination, means forming a sealedcasing having a substantially vertical wall externally of which ismounted a gong, said wall having an opening adjacenta partof thegong tobe struck and a re-entr-anttube-like casing part extending from saidopening inwardly and upwardly into the interior of the sealed casing andforming an air trap to prevent rise of water thereinto, aparamagneticplunger slidable in said tube-like casing part and protected againstwater by said air trap, said plunger having striker means operating uponsaid gong portion through said opening, means for holding said strikermeans in an at-rest position out of contact with said gong to preventwater accumulation and freezing thereat and for actuating said plungerto cause striking of said gong comprising permanent magnet means withinsaid sealed casing and having pole extensions axially spaced relative tothe axis of said re-entrant tube-like casing part to produceunidirectional magnetic flux within said 're-entrant casing part, saidplunger having two parts, oneof which is acted upon by said flux to holdit and said striker means against descent into engagement with saidgong, said part being of varying cross-section to increase thereluctance in the path of flow of said flux upon downward movement ofthe plunger, and an electro-magnetic winding within said sealed casingand producing, when energized, a magnetic field acting through the wallsof said reentrant tube-like casing part and upon the other part of saidplunger.

16. In a signallingconstruction, in combination, means forming a sealedcasing and comprising at least two separable casing parts and providedwith-means forming a sealed connection therebetween, a wall member, saidsealed casing means having an aperture with a re-entrant tubelikecasing'part extending from said aperture inwardly and upwardly into theinterior of the sealed casing and forming an air trap to prevent rise ofwater thereinto, a signalling device supported externally of said casingand in operative relation to said aperture, and means for activatingsaid signalling device comprising a movable paramagnetic member in saidre-entrant tubelike casing part and protected against water by said airtrap and having means responsive to its movement and operable throughsaid aperture for activating said signalling device and means forcontrolling actuation of said movable paramagnetic member and comprisingelectromagnetic means within said sealed casing for coacting through thewalls of said re-entrant tube-like casing part to effect movement ofsaid paramagnetic member.

1'7. In a signalling construction, in combination, means forming asealed casing that has an inwardly and upwardly extending casing partthat is re-entrant from an opening in a wall of the casing and therebyforming an air trap to prevent rise of water thereinto, a signallingdevice external of said casing and operatively related to said opening,and means for activating said signalling device comprising a movableparamagnetic member in said re-entrant casing part and :plungeractuating means including electro-magnetic means within said sealedcasing for coacting magnetically through the walls of said re-entrantcasing part with'said paramagnetic "member.

18. In a signalling construction, in combination, means forming a sealedcasing having a substantially vertical wall externally of which ismounted a gong, said wall having an opening adjacent a part of the gongto be struck and a re-entrant tube-like casing part extending from saidopening inwardly upwardly into the interior of the sealed casing andforming an air trap to prevent rise of water thereinto, a paramagneticplunger slidable in said tube-like casing part and protected againstwater by said air trap, said plunger having striker means operating uponsaid gong portion through said opening, and means for actuating saidplunger comprising electromagnetic means within said sealed casing forproducing a magnetic flux that operates upon said plunger through thewall of said re-entrant tube-like casing part.

19. In a signalling construction as claimed in claim 18 in which saidgong has a dished portion that overlies and covers over said opening andin which said re-entrant tube-like casing part extends at an angle tothe central vertical axis of the gong with its axis intersecting thegong at a point displaced from said vertical gong axis whereby the gongportion struck by said striker means is of an angularity or curvature toprevent accumulation of water thereat.

20. In a signalling construction, in combination, means forming a sealedcasing and com prising at least two separable cas ng parts provi ed withmeans forming a sealed connection therebetween, one of whi h parts hasan inwardly and upwardly extending casing part that is re-entrant froman opening therein and thereby forming an air trap to prevent rise ofwater into said re-entrant casing part, a signalling device external ofsaid casing and operatively related to said opening, means foractivating said signalling device comprising paramagnetic means in saidre-entrant casing part and protected against water by said air trap withmeans within said sealed casing for producing a magnetic flux forcoaction through the walls of said reentrant casing part with saidparamagnetic means, and means for securing said two separable casingparts together and including means preventing assembly to the other partof that casing part which has the re-entrant casing part with the latterin inverted position.

21. In a signalling construction, in combination, means forming a sealedcasing having mounted externally thereof a gong with its axissubstantially horizontal and with the concave side thereof toward thecasing means, said casing means comprising at least two separable casingparts provided with means forming a sealed connection therebetween, oneof said parts having an opening with which the open end of a tubememher, which extends into the interior of said casing and is closed offat its inner end, is in sealed connection, the line of the axis of saidtube member as extended through said open end intersecting said concaveside of said gong at a point below the diameter of the gong anddisplaced from the vertical diameter thereof, movable paramagnetic meansin said tube member for activating said gong through the outer open endthereof and operating thereon at substantially said point on the concaveside of said gong, and means within said sealed casing for producingmagnetic flux which acts upon said paramagnetic means through the wallsof said tube member.

22. In a signalling construction, in combination,

means forming a sealed casing and comprising at least two separablecasing parts provided with means forming a sealed connectiontherebetween, one of said parts having an opening with which the openend of a tube member, which extends into the interior of said casing andis closed off at its inner end, is in sealed connection, a signallingdevice external of said casing and operatively related to said opening,movable paramagnetic means in said tube member for activating saidsignalling device through the outer open end thereof, and means withinsaid sealed casing for producing magnetic flux which acts upon saidparamagnetic means through the walls of said tube member, said tubemember extending into said sealed casing in upward direction and formingan air trap to prevent rise of water thereinto, and slidably supportingand guiding said paramagnetic means, and means responsive to slidableactuation of said paramagnetic means and coacting with said signallingdevice through the outer open end of said tube member.

23. In a ignalling construction. in combination, means forming a sealedcasing and comprising at least two separable casing parts provided withmeans forming a sealed connection therebetween, one of said parts havingan opening with which the open end of a tube member, which extends intothe interior of said casing and is closed off at its inner end, is insealed connection, a signalling device external of said casing andoperatively related to said opening, movable paramagnetic means in saidtube member for activating said signalling device through the outer openend thereof, and means within said sealed casing for producingmagnetic'flux which acts upon said paramagnetic means through the wallsof said tube member, said opening being in a substantial- 1y Verticalwall portion of the casing part and said tube member extending upwardlyinto the sealed casin at an acute angle to said substantially verticalwall.

24. In a signalling construction as claimed in claim 23 in which theopen end portion of said tube member projects downwardly at an acuteangle through and beyond said opening to the exterior of the casing walland forms a water shed.

25. In a signalling construction as claimed in claim 23 in which saidflux-producing means comprises electromagnetic winding means having anaxial bore therein dimensioned to slide over said tube member and beingthereby sleeved onto the latter from the inner end thereof for producinga magnetic field acting upon said plunger means through the walls ofsaid tube member, said winding means having a framelike support meanstherefor that falls in a plane parallel to the axis of said bore andsaid casing having internal support means that extends at said acuteangleto said vertical wall to slidably receive thereon said frame-likesupport.

26. In a signalling construction, in combination, means forming a casinghaving an opening in a wall thereof with one end of tube member rigidlysecured thereto at said opening and extending inwardly of said casinglike a cantilever, a gong supported externally of said casing with aportion thereof adjacent said opening, paramagnetic plunger means insaid tube member and having striker means operable upon said gongthrough the outer end of said tube member, a control unit comprisingspaced pole piece mem bers, electro-magnetic winding means and permanentmagnet means coacting therewith to proplunger means in an at-restposition.

2'7. In a signalling construction, in combination, means-forming a.casing having an opening in a wall thereof withone end of a cantilevertube member rigidly, secured thereto'at said opening and extending.inwardly of said casing, a gong presenting aperipheralportion thereofadjacent saidopening, said casing and said gonghaving interfitting meansfor non-rotatively securing said gongatits center to said casing-toprevent presentation of any other peripheral portion thereof 'to saidopening, paramagnetic plunger means in said tube member and havingstriker ,meansoperable upon said-peripheral portion of said gong throughthe .outer end of said tube member, a control unit sleeved onto saidcanti- ',lever tube member from the inner 'end thereof and comprisingelectro-magnetic windingmeans for producing a magnetic field acting uponsaid plunger means through the walls of said 'tube -member'whereby thecoaction'between saidmagnetic field, said plunger means, said strikermeans, and said gongportion may be determined by shifting said controlunit along said tube mem- "ber, said casing havingtherein aguidewaydorming support extendingparallel to and spaced from said'tubemember for slidablyreceiving-said control unit, and means forsecuringsaidunit in adjusted .position along said support, .saidinterfittingmeans, in preventing rotary displacement of said gongportion, ,preventing impairment of the setting of the aforesaidcoaction.

"28. In a signalling construction as claimed in claim '27 in which saidcontrol unit comprises permanent magnet means .pro'ducing a'magneticfield acting upon said paramagnetic means, during de-energization ofsaid winding means, to hold it and said striker in retractedposition.relative to said gong and tube member.

29. In a signalling construction, in combination, ,a supporting frame.carrying a signalling element, movable paramagnetic means for actuatingsaid signalling element, said supporting frame having means movablysupporting said paramagnetic means for coaction withsaid signallingelement, a control unit 'for'holding ,said paramagnetic means in anat-rest position and for actuating it -comprising permanent'magnet meansproducing a magnetic field the flux of which exerts magnetic force onsaid paramagnetic means to hold it in at-rest ,position.andelectromagnetic Winding meansfor producing, when energized, a magneticfield coacting to effect movement of said paramagnetic means,saidsupporting frame having support means by which said control unit ismovably supported relative to saidparamaggnetic meanswherebyitheposition of saidpermanent magnet means and said winding meansrelative to said movable paramagnetic means may be determined, and meansfor securing said control unitin position.

30. In a signalling construction, in combination, a supporting framecarrying a signalling element, movableparamagneticmeans-for actuatingsaid signalling element, said-supporting frame 28 having means movablysupporting said paramagnetic means for coaction with said signallingelement, a control unit forholding said paramagnetic means in an at-restposition and for actuating it comprising permanent magnet meansproducing a magnetic field the flux of which exerts magnetic force onsaid paramagnetic means to hold it in at-rest position andelectromagnetic windingmeans for producing, when energized, a magneticfield coacting to eiiect movement of saidparamagnetic means,said;permanent magnet means and said winding means having meansinterrelating both to a common flux gap across which the fiux of bothmagnetic means is effective whereby the flux of said winding means, whenenergized, by alternating current, is alternatelyadditive to andsubtractive from the flux of said permanent magnet means, saidsupporting frame having support means by which said control unit ismovably supported relative to said paramagnetic means whereby theposition of said permanent magnet means and said winding means relativeto said movable paramagnetic means may be-determined, and means forsecuring said control unit in position.

31. In a signalling construction, in combination, a supporting framecarrying a signalling element, movable paramagnetic means for-actuatingsaid signalling element, said supporting frame having means movablysupporting said paramagnetic means for coaction with said signallingelement,;a control unit for holding said paramagnetic means in anat-rest position and foractriatingit comprisingpermanent magnet meansproducing a magnetic field the flux of which exerts magnetic force onsaid paramagnetic means to hold it in at-rest position andelectromagnetic winding means for producing, when energized, a magneticfield coacting to effect movement of said paramagnetic means,'saidcontrol unit carrying a rectifier in .circuit with said winding meanswhereby the latter produces its magnetic field only on alternatinghalf-waves of energizing alternating current, said supporting framehaving support means by which said control unit is movably supportedrelative to said paramagnetic means whereby the position of saidpermanent magnet means and said winding means relative to said movableparamagnetic means may be determined, and means for securing saidcontrol unit in position.

32. In a signalling construction, in combination, a supporting framecarrying a signalling element, movable paramagnetic means foractuatingsaid signalling element, said supporting frame having meansmovably supporting said paramagnetic means .for coaction with saidsignalling element, a control unitfor holding said paramagnetic means inan at-rest position and for actuating it comprising permanent magnetmeans producing .a magnetic field the flux of which exerts magneticforce on said paramagnetic means to hold it in .at-rest position andelectromagnetic winding means for producing, when energized, a magneticfield coacting to effect movement of said paramagnetic means, saidpermanent magnet means of said control unit having spaced extensionpoles forming a flux gap to which said paramagnetic .means is subjectedfor being held in at-rest position, said flux gap being substantiallyindependent of the fluxof themagneticfield of said winding means, saidsupporting frame having support means by which said control unit ismovably supported relative to said paramagnetic means whereby theposition of said permanent magnet means and said winding means relativeto said movable paramagnetic means may be determined, and means forsecuring said control unit in position.

33. In a signalling construction, in combination, a supporting framecarrying a signalling element, movable paramagnetic means for actuatingsaid signalling element, said supporting frame having means movablysupporting said paramagnetic means for coaction with said signallingelement, a control unit for holding said paramagnetic means in anat-rest position and for actuating it comprising permanent magnet meansproducing a magnetic field the flux of which exerts magnetic force onsaid paramagnetic means to hold it in at-rest position andelectromagnetic winding means for producing, when energized, a magneticfield coacting to effect movement of said paramagnetic means, saidcontrol unit carrying a current interrupter in circuit with said windingmeans and coacting with magnetic flux produced thereby for energizingsaid winding means in successive pulses of energizing current, saidsupporting frame having support means by which said control unit ismovably supported relative to said paramagnetic means whereby theposition of said permanent magnet means and said winding means relativeto said movable paramagnetic means may be determined, and means forsecuring said control unit in position.

34. In a signalling construction, in combination, a supporting framecarrying a signalling element, movable paramagnetic means for actuatingsaid signalling element, said supporting frame having means movablysupporting said paramagnetic means for coaction with said signallingelement, a control unit for holding said paramagnetic means in anat-rest position and for actuating it comprising permanent magnet meansproducing a magnetic field the flux of which exerts magnetic force onsaid paramagnetic means to hold it in at-rest position andelectromagnetic winding means for producing, when energized, a magneticfield coacting to effect movement of said paramagnetic means, saidpermanent magnet means of said control unit having a plurality ofextension poles between which are formed two spaced flux gaps forpermanent magnet flux and into either of which said paramagnetic meansis movable, said winding means coacting with at least one of said fluxgaps to affect the permanent magnet flux therein, said supporting framehaving support means by which said control unit is movably supportedrelative to said paramagnetic means whereby the position of saidpermanent magnet means and said winding means relative to said movableparamagnetic means may be determined, and means for securing saidcontrol unit in position.

35. In a signalling construction, in combination, a supporting framecarrying a signalling element, movable paramagnetic means for actuatingsaid signalling element, said supporting frame having means movablysupporting said paramagnetic means for coaction with said signallingelement, a control unit for holding said paramagnetic means in anat-rest position and for actuating it comprising permanent magnet meansproducing a magnetic field the flux of which exerts magnetic force onsaid paramagnetic means to hold it in at-rest position andelectromagnetic winding means for producing, when energized, a magneticfield coacting to effect movement of said paramagnetic means, saidpermanent magnet means on said control unit having a plurality of spacedpoles to provide two flux gaps for the permanent magnet flux that coactswith said paramagnetic means and said winding means being relatedthereto to alternately change, upon energization by alternating current,the effective flux values of said two flux gaps and thereby efiectactuation of said movable paramagnetic means, said supporting framehaving support means by which said control unit is inovably supportedrelative to said paramagnetic means whereby the position of saidpermanent magnet means and said winding means relative to said movableparamagnetic means may be determined, and means for securing saidcontrol unit in posi tion.

36. In a signalling construction, in combination, a signalling elementand a reciprocable striker and paramagnetic plunger means thereforhaving means guiding them for reciprocation in reversible strokes, saidparamagnetic plunger means comprising two paramagnetic plungers havingmeans mechanically inter-relating them for movement in the samedirection on each stroke and for movement of one relative to the other,and magnetic flux-producing means controlling said paramagnetic meansand comprising permanent magnet means acting thereon to hold it and saidstriker in an at-rest position and electro-magnetic winding meanscoacting upon energization to reciprocate both plungers for strikingactuation of said striker and, upon one of said plungers becomingimmovable, to reciprocate the other plunger relative thereto.

37. A signalling construction as claimed in claim 36 in which saidpermanent magnet means is provided with extension poles spaced along theline of movement of said paramagnetic means to provide an axial flux gapfor one of said plungers to coact with for being held in said at-restposi tion, said electromagnetic winding means and said other plungerbeing magnetically interrelated so that the flux of said winding actsupon said other plunger substantially independently of said axial fluxgap.

38. A signalling construction as claimed in claim 36 in which saidpermanent magnet means is provided with extension poles spaced along theline of movement of said paramagnetic means to provide an axial flux gapfor one of said plungers to coact with for being held in said atrestposition, said electromagnetic winding means being magneticallyinterrelated to said extension poles so that flux produced by it whenenergized coacts with permanent magnet flux in said axial flux gap toeffect reciprocating actuation of both plungers and to effectreciprocation of only one of them when the other becomes immovable.

39. A signalling construction as claimed in claim 36 in which saidpermanent magnet means is provided with a plurality of spaced extensionpoles spaced along the line of movement of said paramagnetic plungermeans to provide several axial flux gaps for permanent magnet flux whichcoact to hold said paramagnetic means in at-rest position and in whichsaid electromagnetic winding means coacts, when energized, to causeeffective flux values in said two axial flux gaps to be alternatelypreponderant over each other and thereby effect reciprocation of saidparamagnetic plunger means and upon one of said plungers becomingimmovable and thus becoming a stationary part of the magnetic circuit,to efiect reciprocation of the-other plunger relative thereto.

40. In a signalling construction, in combination, means forming a sealedcasing that has an inwardly and upwardly extending tubelike casing partthat is .re-entrant from .an

opening in a wall of the casing :and there- 'by forming an air trap toprevent .rise of water thercinto a signalling device external of saidcasing-and operatively related to said opening, reciprocableparamagnetic plunger means -in :saidtube-like re-entrant casing part andhaving a part which, uponreciprocation of said plunger means, coactsthrough said opening withsaid signalling device, said-signalling devicebeingpositioned in the path of reciprocating movement of "said plungerpart whereby the signalling'de- -vice may act to block removal of saidplunger means and plunger part from said re-entrant .casing part, andplunger-actuating means including electro-magnetic 'means within saidsealed casing for coacting, when energized, magnetically through thewalls of said re-entrant casing -gpart with said plunger means forreciprocating thelatter and permanent magnet means within said sealedcasing for eoacting magnetically through the wallsofsaidre-entrantcasing part with said paramagnetic plunger meansandproviding a magnetic field operating upon the latter, duringdeenergization of said electromagnetic means, to hold said plunger meansin inwardly .retracted position relative to said re-entrant casing partand thereby hold said plunger partaway from said signalling device.

References Cited in the file of this patent UNITED STATES PATENTS

